Part 1 explained what has happened to your muscles and how nerve injury works. The natural question that follows is: what can be done about it?
The answer, for much of this book, is electrical stimulation. But the phrase "electrical stimulation" covers an enormous range of techniques and devices. A pain-relief device (TENS unit), a standard muscle-strengthening device, and a specialist stimulator for denervated muscle are all forms of electrical stimulation, but they differ profoundly in what they do and how they work.
Part 2 explains these differences. Chapter 4 describes how electrical stimulation works and why denervated muscle requires a fundamentally different approach. Chapter 5 reviews what the research actually shows: the evidence that this treatment works, how well it works, and its limitations. Chapter 6 addresses the questions and concerns you are most likely to have, with honest answers.